By Guy Faulconbridge and Humeyra Pamuk

LONDON/WASHINGTON (Reuters) -U.S. Central Intelligence Agency Director William Burns was expected to caution President Vladimir Putin’s spy chief at talks on Monday about the consequences of any use of nuclear weapons, and to raise the issue of U.S. prisoners in Russia, a White House official said.

Kremlin spokesman Dmitry Peskov confirmed to Russian news agencies that a U.S.-Russia meeting had taken place in the Turkish capital Ankara but declined to give details about the participants or the subjects discussed.

The White House spokesperson, speaking on condition of anonymity, said Burns was meeting Sergei Naryshkin, head of Russia’s SVR foreign intelligence service.

It was the first known high-level, face-to-face U.S.-Russian contact since Russia invaded Ukraine in February.

“He is not conducting negotiations of any kind. He is not discussing settlement of the war in Ukraine,” the spokesperson said.

“He is conveying a message on the consequences of the use of nuclear weapons by Russia, and the risks of escalation to strategic stability … He will also raise the cases of unjustly detained U.S. citizens.”

Burns is a former U.S. ambassador to Russia who was sent to Moscow in late 2021 by President Joe Biden to caution Putin about the troop build-up around Ukraine.

“We briefed Ukraine in advance on his trip. We firmly stick to our fundamental principle: nothing about Ukraine without Ukraine,” the spokesperson said.

Putin has repeatedly said Russia will defend its territory with all available means, including nuclear weapons, if attacked. He says the West has engaged in nuclear blackmail against Russia.

MANY OUTSTANDING ISSUES

The remarks raised particular concern in the West after Moscow declared in September that it had annexed four Ukrainian regions that its forces partly control.

The U.S.-Russian contact in Turkey was first reported by Russia’s Kommersant newspaper. The SVR did not respond to a request for comment.

Beyond the war, Russia and the United States have a host of outstanding issues to discuss, ranging from the extension of a nuclear arms reduction treaty and a Black Sea grain deal to a possible prisoner swap and the Syrian civil war.

U.N. Secretary General Antonio Guterres, asked at a summit of the Group of 20 (G20) leading economies in Indonesia about the meeting in Turkey, said the United Nations was not involved.

Biden said this month he hoped Putin would be willing to discuss seriously a swap to secure the release of U.S. basketball star Brittney Griner, who has been sentenced to nine years in a Russian penal colony on drugs charges.

Former U.S. Marine Paul Whelan, who holds American, British, Canadian and Irish passports, was sentenced in 2020 to 16 years in a Russian jail after being convicted of spying, a charge he denied.

Viktor Bout, a Russian arms dealer jailed in the United States, has been mentioned as a person who could be swapped for Griner and Whelan in any prisoner exchange.

(Reporting by Reuters; Additional reporting by Jonathan Spicer in Turkey; Editing by Gareth Jones)

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